Answer: C. Semantic Search Engines
Explanation: 
Semantic search is simply search with meaning. It is designed to locate information based on the nature and meaning of Web content, not simple keyword matches (like in lexical searches)
 
        
             
        
        
        
Out door air pollution has been a problem since ancient Romans...but the industrial revouloution was when outdoor air pollution increased and it a significant problem...
hope this helps
        
             
        
        
        
The two main
capabilities involved in visual literacy are:
<span>1)   </span>Communication through use of visual elements.
<span>2)   </span>Interpret meaning from visual elements.
<span>Visual literacy is the
capacity to decipher, arrange, and make significance from data displayed as a
picture, broadening the importance of proficiency, which means understanding of
a composed or printed content.</span>
 
        
             
        
        
        
We are in the modern era and the information era
        
             
        
        
        
Answer and explanation :
the three control problems associated with competing process are
- MUTUAL EXCLUSION : We know that some resources are shareable and some are not shareable. which means only one process can access the resource at a time this type of resources are called critical resources this code can be access at only one process at a time. the other process if required to access should not be allowed 
- DEADLOCK: this hold the process without complete for example suppose there are two resources R1 and R2 and two process P1 and P2 and P1 use R1 and P2 use R2 but after some time when P1 needs R2 but R2 is not available as it is used by P2 so the all process will be on hold
- STARVATION : when priorities are given to the process as high priorities and low priorities. And high priorities process always competing  then low priorities process have to wait for very long time this is called starvation